1. Technical Field
The present disclosure relates to a feed hopper, and more particularly, a feed hopper including a rotatable sleeve.
2. Description of Related Art
With the development of optical technology, plastic lenses are typically manufactured by injection molding machine. The injection molding machine generally includes a feed hopper for feeding plastic granules, a heating cylinder for melting the plastic granules transported from the feed hopper, a reciprocating screw accommodated in the heating cylinder for transporting the melted plastic, an injecting member, and a plurality of molds having a cavity for accommodating the melted plastic. In an injection process of manufacturing plastic lenses, pluralities of plastic granules are firstly fed into the heating cylinder through the feed hopper, the plastic granules are consequently melted and transported by the screw rotating, and then, melted plastic is injected into the cavity of the molds using the injecting member and cooled in the cavity. Finally, the molds are separated from each other, thereby obtaining at least one plastic lens.
In actual operation, plastic granules fed into the heating cylinder may be more than the required amount. Resultantly, after finishing manufacturing predetermined amount of lenses, a plurality of plastic granules may be retained in the feed hopper. As being exposed to external environment, the moisture in the atmosphere changes the physical properties of the retained plastic granules, and makes it no longer suitable for making lenses. Generally, for purpose of removing the retained plastic granules, the retained plastic granules are melted in the heating cylinder and then spouted out of the injection mold machine with the injecting member. However, this costs much more time and waste materials.
Therefore, what is needed is feed hopper to overcome the problems described mentioned.